There is a familiar drilling apparatus that contains a hollow body with rock-destroying components --rollers --attached to it. A replaceable cylinder is arranged in the body and is fixed by pins to the body. A transition piece to the bit is attached to the body by a screw-coupling. Inside this transition piece and axially to the body is housed a sliding case with a subassembly for generating hydrodynamic waves, with lateral channels and a central channel. Fixtures that are resistant to wear are mounted in the channels. The transition piece to the bit has an inner flange that serves as support for a spring that embraces the case and works with the flared flange of the case.
After the drilling apparatus is inserted into a drill hole, flushing first takes place through the central channel of the sliding case. In the process, a force determined by a pressure difference at the fixture arranged in the central channel acts upon the flared flange of the case. The spring is compressed by the action of this force until the lateral channels come to rest under the frontal surface of the cylinder. The lateral channels open in the process and liquid pressure in the case drops enough for the spring to bring the case back upward until these channels are covered, and the cycle repeats itself. When the case moves downward the flushing liquid situated in the space between the case and the transition piece to the bit is expelled upward through overflow openings.
The frequency of the pendulum movements of the case can be adjusted by the pumping capacity and the cross-sectional surface of hydromonitor attachments.
Known drilling apparatuses are inadequate for current demands on drilling technology and do not ensure the sinking of a drill hole for the following reasons:
the generated hydrodynamic pulsations of the drill liquid do not contribute to destroying the rock due to their low frequency and slight amplitude and do not ensure an increase in drilling characteristics--mechanical speed and bit base length; PA1 the complexity of construction from the perspective of production and assembly increases production costs; PA1 the presence of movable subassemblies and elements in the construction does not guarantee the required service life and reliability, in particular in an abrasive medium of drill liquid. PA1 c.sub.1 is the acoustic velocity in the metal; PA1 n is the refractive index.